YOI,
Many of us with SPF's have experienced this problem.
More than likely it is the throttle linkage. Unfasten each ball connection and grease the fittings. This should eliminate the problem. There could be some other problem, but this solution seems to work in most cases. Also check to make sure the assembly is not hanging up when it makes its bends. This has been discussed at some length on "SCOF" the SPF forum.
TL
